Microphone amplifier



June 29, 1943. A. J. MAsTRoPoLE 2,322,765 /MICROPHONE AMPLIFIER Filed Aug. 5, 1940 5 Sheets-Sheet 1 INVENTOR ATTORNEY June 29, 1943.

`A. J. MAsTRoPoLE 2 MICROPHNE AMPLIFIER s shets-sneet FilGd- Aug. 5, 1940 IN V EN TOR.

ATTORNEY June 29, 1943. A. J. MAsrRoPoLE MICROPHONE AMPLIFIER Filed Aug. 3, 1940 y 3 Sheets-Sheet 3 INVENToR. m FP50 J. M45/Topaz f SMMJ LA,

Patented June 29,

' MICROPHONE AMPLIFIER Alfred J. Mastropole, New York, N. Y., assignor to f Sonotone Corporation, Elmsford,

poration of New York Application August 3, 1940, Serial No. 350,245

6 Claims.

This invention relates to microphone amplifiers for hearing aids and it has among its objects an improved wearable microphone amplifier which is so combined with the microphone, battery and receiver of the wearable hearing aid as to permit quick change-over from amplified operation with the amplifier operatively connected between the receiver and the microphone, to simplified operation with the receiver directly connected to the microphone, Without changing the operative correlation of the terminals interconnecting the microphone, the receiver, the battery and the cord.

The foregoing and other objects of the invention will be best understood from the following description of exemplifications thereof, reference being had to the accompanying drawings wherein Fig. 1 is a vertical cross-sectional view along line I-I .of Figs. 2 and 3 illustrating a hearing aid microphone amplifier exemplifying one form of the invention;

Iilg. 2 is a cross-sectional view along line 2--2 of Fig. 1;

Fig. 3 is a cross-sectional view along line 3-3 of Fig. 1;

Fig. 4 is a cross-sectional view along line l--l of Fig. 3;

Fig. 5 is a bottom view of the amplifier shown in Figs. l and 2, parts being broken away to show the interior elements thereof;

Fig. 6 is a diagrammatic partially exploded view illustrating the mechanical as well as the electrical relationship of the elements of the amplier and the cooperating parts of a wearable hearing ald; and Y Fig. '7 is a view similar -to Fig. 6 illustrating another exempliiication of the invention.

A typical wearable microphone amplifier hearing aid the general arrangement of which is shown in the diagram of Fig. 6 usually consists of a microphone I0, a control unit Il, a hearing inducing receiver I2, a microphone amplifier unit I3 having an actuating winding I4 and an amplifier microphone I5, which are energized by a battery I6 and are interconnected by a cord I1, which usually has a detachable plug I8 for connecting it to the amplifier unit, the battery being usually connected to the circuit through two battery plugs 2|, 22 extending from the microphone amplifier casing and engaging terminal sleeves Il of the battery.

When the microphone amplifier is connected in the circuit, the control unit I I, which is usually housed together with the microphone III in a small fiat casing, completes a connection from N. Y., a corthe positive battery terminal I9, through the amplifier battery terminal 2 I, by way of a terminal member 23 of the amplifier unit, to a lead of the cord Il, and a slider contact of the control unit II to one electrode of the microphone, and back from the other microphone electrode, through a cord lead to the amplifier cord terminal 24, and therefrom by way of a suitable lead 25 in the amplifier to one end of the amplifier actuating coil I4the other end of which is con--v nected through a lead 26 to the other amplifier battery terminal 22, which engages the battery terminalof opposite polarity; the output circuit of the yamplifier being at the same time completed from the positive battery supply terminal I9, through the vpreviously traced connection to the slider contact of the control unit II, and therefrom over the rheostat of the control unit, the cord lead including windings of the receiver I2 to the amplifier cord terminal 21, and therefrom through the connections including the amplifier lead 28 to one electrode of the amplifier microphone, the other electrode of which is connected through lead 26 to the amplifier battery terminal 22 which engages the negative terminal of the battery I6.

When the control unit II is in the position shown, the microphone Iii is thus connected in series with the amplifier winding I 4 for actuating the amplifier microphone I 5 with modulated speech frequency input currents, and the rheostat of the control unit connects the battery in series with the receiver I2 and the amplifier microphone I5 for actuating the receiver with amplified output currents.

Such amplifier microphone is usually housed in a casing having a bottom wall held on the top of the battery I6 by its two terminal plugs 2 I, 22, which engage the terminal sleeves of the battery so as to form a mechanical as well as an electrical connection between the amplifier unit and the battery and join them into a single unit which may be conveniently hidden in a pocket of the user.

In accordance with the invention, the part of the microphone amplifier unit in which are anchored the terminal members through which the connection to the battery is made and the part of the amplifier unit in which are anchored the terminals through which the connections to the cord circuit are made, are arranged in the form of two switch members which are relatively movable between one position in which the two switch members interconnect the microphone amplifier between the microphone and the receiver and another position in which the receiver is directly connected to the microphone. y

" Figs. l to illustrate the structural features of one form of such microphone amplifier, Fig.

I6 illustrating diagrammatically inv an exploded perspective view the functional relationship of the switching elements vof the amplifier unit. The casing of the amplifier unit has a bottom `wall 3l made, for instance, of `a synthetic resin molding, and having at one end a terminal block in which are embedded the three terminal bushings 23, 24,21, as in the usual microphone amplif fiers, a housing cover 32 being sultablysecured, as by screws, to ledges 33 extending along the edges of the base plate to complete the housing.

On s suitable upwardly projecting bracket arm 35 extending, for instance, from a contact plate 36 embedded in the molded bottom wall 3| is secured the microphone 'amplifier assembly which may be constructed, for instance, intlie way described in the copending application Serial No. 328,336, filed April 6, 1940. The anchoring element 36 of the supporting bracket 35 has an extension which serves as a contact strip 4Iy which, together with similar cooperating contact strips 42, 43, 44, 45, are secured, as by molding, withinI the bottom wall 3l s o as to expose their outer contact surfaces flush with thesurface of the bottom wall, to the interior of the amplifier housing. v

The contact surfaces 4I to 45 are arranged to slidably cooperate with contact pins 5I. 52, 53,

54 mounted at they ends of contact spring arms recess 65 formed on the outer side of the bottom wall 3|, threaded studs of the two battery plugs 2 I, 22 and an additional screw 66 engaging the inwardly threaded surface of the three bushing rivets 6I, 62, 63 so as to hold the two mounting plates 68 and 64 slidably clamped to the oppositel sides of the central portion of the bottom wall Y 3| and to permit slidable movement of the switching contacts 5I to 54 of the mounting plate 58 relatively to the switching contacts 42 to 45 of the bottom wall to establish in the position shown the wall portion 64 is slidably movable. The two arms of spring 1I have ends 13, 14 bent outwardly in opposite direction and engaging holes 13', 14 in the slidable wall portion 64 andthe facing wall of the recess depression l2 so that if the base the switch mechanism are combined in a self-supporting switch unit suitable for plugging into the socket sleeves i3l of the battery unit, the switch unit being provided with socket sleeves 8l, 82 into which a distinct amplier unit 88 is plugged in. The switch unit has a bottom wall 3| with battery terminal plugs 2i, cord bushings and switch elements as in Figs. l to 6except that the cord bushings 23, 24, 21 are below the level of its switch contact surface, and that the bracket support 35 for the amplifier unit-is eliminated, so that the upper surface of the bottom wall 3| provides a fiat surface for guiding the enlarged switch plate 83 `to which the battery terminal plugs 2s, 22 are clamped. The two bushings tl,

62 extending from the contact spring arms 55, 56, respectively, and holding clamped to the switch plate 83 the downwardly extending battery plugs 2i, 22, have upwardly extending terminal sleeves 6i, 82 so that a self-contained standard microphone amplifier unit may be detachably mounted on the switchplate 83 by plugging the battery terminals 2i', 22' of such amplifier unit into the terminal sleeves et, a2 of the switch plate as. A cover plate 84 having holes for the terminal -sleeves 6l, 82 is secured, as by screws 85, to the upper surface of the switch plate 83, and provides a seat for the base of the amplifier unit 80.

The switch bottom'wall 3I is also provided with a cord extension having two leads 25, 28 which are connected with a two-prong plug to the cord terminal bushings 24, 21 of the standard amplifier unit 80 so as to complete circuit connections from its winding I4 and microphone I5 to the switchA contacts 44, 45 in a way analogous to the similar connections established in the arrangement of Fig. 6.

'Ihe principles of the invention explained in the amplifier interconnections, and inthe other position a direct operating connection between the microphone and the receiver.

The amplifier unit has its actuating windingv I4 and its amplifier microphone interconnected between the contact plates 4 I, 44, 46vof the bottom wall so that when the contacts 5I to 54 which carry the battery terminals are in the position shown in the drawings, the amplifier is connected between the microphone and the receiver, and that when the contacts associated with the battery terminals 2I, 22 are in the dotted-line positions indicated in Fig. 6, the microphone I0 is connected directly with the receiver under the elimination of the amplifier, the amplifier being cut out from the operating circuit.

The casing wall portions 64, 58 to which the battery terminal plugs 6 I, 62 are secured is biased to either one or the other switching positions by a toggle spring 1I formed of a wire having two spring arms confined in a shallow depression 12 in the inner wall surface of the recess 65 in which will suggest to those skilled in the art many other applications and modificationsof the same. It is accordingly desired that the appended claims be construed broadly, and that they shall not be limited tothe specific details shown and described in connection with exemplifications thereof.

I claim:

1. In a microphone amplifier unit for a hearing aid device comprising atransmitter microphone unit, a receiver unit, a batteryuni't and cord leads interconnecting the microphone unit, the

receiver unit and the amplifier unit: a mounting member having battery terminals for interconnecting said amplifier unit to said battery unit; a supporting member for said amplifier unit movably mounted on said mounting member for movement between two positions; switch means having contact elements secured to said mounting member and contact elements secured to said supporting member and arranged to establish two different sets of circuit connections in said two positions of said supporting member; an amlated,

piiiier microphone; ating said ampliiier minals carried by interconnected to ampliiier windings ior actumicrophone; cord lead tersaid supporting member and the contact elements of said `supporting member; -the contact elements o f said of said mounting means establish in interconnected to the contact elements of' said cuit,and that in the other position oi' said supporting member said switch means establish in conjunction with said cord leads a circuit connecting said microphone unit and said receiver unit directly in s eriesv with said battery unit; said mounting member and said supporting memberhaving substantially parallel facing surfaces for guiding said supporting member from one position to the other position,

2. In a microphone ampiiiier unit for a hearing aid device comprising a transmitter microphone unit, a receiver unit, a battery unit and`,cord leads interconnecting the microphone unit, the receiver unit and the ampliiler unit: a mounting member having battery terminals'ior interconnecting said ampliiier unit to said battery unit; a supporting member for said ampliiier unit movably mounted on said mounting member for movement between two positions; switch means having contact elements secured to said mounting member and contact elements secured to said supporting 'member and arranged to establish two diii'erent sets of circuit connections in said two positions of 'said supporting member; an amplifier-microphone; amplifier windings for actuating said amplifier microphone; cord lead ter, minals carried by said supporting member and interconnected to'the contact elements of said suppcrtingniember; the contact elements of said switchingl means being so arranged and correlated, and the contact elements of said mounting member being so interconnected with saidbattery terminals that-in one position of said supporting member said switch means establish in conjunction with said cord leads an input circuit interconnecting said battery unit in series with said ampli'iier windings and said microphone unit, and an output circuit interconnecting said battery unit in series with said amplifier microphone and said receiver unit for supplyingto said receiver unit amplified output currents corresponding to input currents in said input circuit.and that in the other position of said supporting member said switch means establish in conjunction with said cord leads a circuit connecting said microphone unit and said receiver unit directly in series with said battery unit; said mounting member and said supporting member having substantially parallelfacing surfaces for guiding saidsupporting member from one position to the other position; said battery terminals projecting outwardly trom said mounting member and being arranged for slidable engagement with a part oi' said battery unit so as to form therewith a structure supporting said ampliiier unit.

3. In a microphonev ampliiler unit ior a hearing member and contact elements 3 lng aid,device comprising a transmitter microphone unit, a receiver unit, a battery unitand cord leads interconnecting the microphone unit, the receiver unit and the ampliiier unit: a moimting member having battery terminals i'or interconnecting said ampliiler unit to said battery unit; a supporting member for said amplifier unit movably mounted lon said mounting member for movement between two positions; switch means having contact elements secured to said mounting member and contact. supporting member yanc! arranged to establish two diierent sets ci' circuit connections in said two positionsof said supporting member; an am.

plier microphone; ampliiler windings yfor actuating said ampliiier microphone; cord lead terminals carried by said supporting member and supporting member; the contact elements of said switching means being so arranged and correlated, and the contactelements of said mounting member being so interconnected with said battery terminals that-in one position of said sup porting member said switch means establish in conjunction with said cord leads an input circuit interconnectingsaid battery unit in series with :said ampliiier windings and .said microf phone unit. and an output circuit interconnecting said battery unit in series with said amplifier microphone and said receiver unit for supplying to said receiver unit ampliiled output currents corresponding to intput currents in said input circuitand that in the other positionoi' said supporting member said switch means establish in commotion with said cord leads a circuit connecting said microphone unit and said receiver unit directly in series with said battery unit; said mounting member and said supporting member having substantially parallel facing surfaces for V guiding said supporting member from one position to the other position; said mounting member and said supporting member being mechanically joined and being arranged to constitute with said switching means a self-supporting unit separable from said amplifier unit.

4. In a microphone ampliiler unit for a hearing aid device comprising a transmitter microphone unit, a receiver unit, a battery unit and cord leads interconnecting the microphoneunit, the receiver unit and the amplifier unit; a mounting member having battery terminals for interconnecting said amplifier unit to said battery unit; a supporting member for said 1ampliiier unit movably mounted onrsaid mounting member for movement between two positions; switch means having contact elements secured to said mountg secured to said supporting member and arranged to establish two diil'erent sets of circuit connections in said two positions of said supporting member; an amplifier microphone; amplifier windings for actuating said ampliner microphone; cord lead terminals carried by said supporting member and interconnected to the contact elements of said supporting member; the contact elements of said switching means being so arranged and correlated, and the contact elements of said mounting member being so interconnected with said battery terminals that--inL one position of said supporting member said switch means establish in commotion with said cord leads an input circuit interconnecting said battery unit in series with said ampliiier windings and said microphone imit, and an output circuit interconnecting said battery unit in series '75 with said ampliiier microphone and said receiver elements secured to saidunit for supplying to said receiver unit ampliiied .so as to form therewith a structure supporting vsaid amplier unit; said mounting member and said supporting member being mechanically .joined and being arranged to constitute with said switching means a self-supporting unit separable from said amplifier unit.

5. In a microphone ampliiler unit for a hearing aid device comprising a transmitter microphone unit, a receiver unit, a battery unit and cord leads interconnecting the microphone unit, the receiver unit and the amplifier unit: a mounting member having battery terminals for interconnecting said amplifier unit to said battery unit; a

housing member for saidampliflerunit movably mounted on said mounting member for movement between two positions; switch means having contact elements secured to said mounting member and contact elements secured to said housing member and arranged to establish two different sets of circuit connections in said two positions of said housing member; an amplifiermicrophone; amplier windings for actuating said amplitier microphone; cord lead terminals carried by said housing member and interconnected to the contact elements or said housingmen-liber; the contact elements of said switching means being so arranged and correlated, and the contact elements of said mounting member being so interconnectedy with said battery terminals thatin one position of said housing member said switch means establish in conjunction with said cord leads an input circuit interconnecting said battery unit in series with said amplifier windings and said microphone unit, and an output circuit interconnecting said battery unit in series with said amplifier microphone and said receiver unit for supplying to said receiver unit ampliiled output currents corresponding -to input currents inv said input circuit,and that in the other position of said housing member said switch means establish in conjunction with said cord leads a circuit connecting said microphone unit and said receiver n unit directly in series with said battery unit; said mounting member and said housing member having substantially parallel facing surfaces for guiding said housing member from one position to the lother position; said housing member forming part of a housing enclosing said ampliiier microphone and said ampliiier windings.

6. In a microphone ampliiler unit for a hearing aid device comprising a transmitter microphone unit, a receiver unit, a battery unit and cord leads interconnecting the microphone unit, the receiver unit and the ampliiier unit: a mounting member having battery terminals ,for intercon-k necting said ampliiier unit to said battery unit: a housing member for said amplifier unit movably mounted on said mounting member for movement between two positions; switch means having contact elements secured to said mounting member and contact elemen-ts secured to said housing member and arranged to establish two different sets of circuit connections in said two positions oi' said housing member; an amplifier microphone; amplifier windings for actuating 4said ampliiier microphone; cord lead terminals carried by said housing member and interconnected to the contact elements of said housing member; the contact elements of said switching means being so arranged and correlated, and the contact elements of said mounting member being so interconnected with said battery terminals thatin one position of said housing member said switch means establish in conjunction with said cord leads an input circuit interconnecting said battery unit in series with said amplier windings and said microphone unit, and an output circuit interconnecting said battery unit in series with said amplier microphone and said receiver unit for supplying to said receiver unit ampliiied output currents corresponding to input currents in said input circuit,-and that in the other position of said housing member said switch means establish in commotion with said cord leads a circuit connecting said microphone unit and said receiver unit directly in series with said battery unit; said mounting member and said housing member having substantially parallel facing surfaces for guiding said housing member from one position to the other position; said battery terminals projecting outwardly from said mounting member and being arranged for slidable engagement ,With a part of said battery unit so as to form therewith a structure supporting said amplier unit; said housing member forming part of a housing enclosing said amplifier microphone and said amplifier windings.

ALFRED J. MASTROPOLE. 

